Deterioration of materials

1. DIFFERENT TYPES
OF DETERIORATION
IN CONCRETE
STRUCTURES
ENGR. NIEVES V. GUARDIAN
ME1 – MATERIALS ENGINEERING

2. D E T E R I O R AT I O N O F C O N C R E T E
S T R U C T U R E S

3. D E T E R I O R AT I O N O F C O N C R E T E
S T R U C T U R E S
• Defect: An identifiable, unwanted condition that
was not part of the original intent of design.
• Deterioration: A Defect that has occurred over a
period of time.

4. D E T E R I O R AT I O N O F C O N C R E T E
S T R U C T U R E S
• Scaling is referred to the loss of the surface portion of concrete (or
mortar) as a result of the freezing and thawing.
• This problem is typically caused by the expansion of water due to
freezing and thawing cycles.
• Scaling happens when the hydraulic pressure from water freezing
within concrete exceeds the tensile strength of concrete
• It is a physical action that usually leaves the aggregates clearly
exposed.
• Usually it start with localized area then extend to larger areas.
• Concrete having decent amount of entrapped air can prevent
scaling damage.

5. DISINTEGRATION
• Disintegration is the physical deterioration (such as scaling) or breaking
down of the concrete into small fragments or particles.
• The deterioration usually starts in the form of scaling and, if allowed to
progress beyond the level of very severe scaling is considered as
disintegration.
• •Severity Light – Loss of surface mortar to a depth of up to 5 mm without
exposure of coarse aggregate;
• Medium - Loss of surface mortar to a depth of 6 to 10 mm with exposure
of some coarse aggregates;
• Severe - Loss of surface mortar to a depth of 11 mm to 20 mm with
aggregate particles standing out from the concrete and a few completely
lost.
• Very Severe - Loss of surface mortar and aggregate particles to a depth

6. EROSION
• Erosion is the deterioration of concrete surface as a result
of particles in moving water scrubbing the surface.
• Similar, damage may be caused by flowing ice.
• Erosion is generally an indication that the concrete is not
durable enough for the environment in which it has been
placed.
• Erosion is sometimes combined with the chemical action
of air and water-borne pollutants which accelerate the
breakdown of the concrete.

7. CORROSION OF
REINFORCEMENT
• When steel corrodes, the resulting rust occupies a
greater volume than the steel. This expansion creates
tensile stresses in the concrete, which can eventually
cause cracking, delamination, and spalling. Steel
corrodes because it is not a naturally occurring
material. Rather, iron ore is smelted and refined to
produce steel. The production steps that transform iron
ore into steel add energy to the metal. The corrosion of
structural steel is an electrochemical process that
requires the simultaneous presence of moisture and
oxygen. Essentially, the iron in the steel is oxidised to
produce rust, which occupies a greater volume than
the steel.

8. CAUSES OF CONCRETE
DETERIORATION
• Chemical
• Physical
• Mechanical
• Defects

9. CHEMICAL
• Deterioration by carbon dioxide
• Deterioration by sulphates
• Deterioration chlorides
• Deterioration Alkali-aggregates
reaction

10. DETERIORATION BY
CARBON DIOXIDE
• Carbonation
• Carbonation is due to the penetration of
CO2 into the concrete.
• This phenomenon consists in the
transformation of the lime (Calcium
Hydroxide)
• This lime (Calcium Hydroxide) then
converts into Calcium carbonate.
• If the concrete gets carbonated it reduces
the ph of the concrete.

11. FFECT OF
CORROSION

12. LEACHING OF THE
CONCRETE
• Formation of lime on the surface
50 to 60 % humidity is very bad.
Can be prevented using air
entrapped concrete.

13. DETERIORATION BY
SULPHATES
• The most common soluble sulphates in
the ground, in water and in industrial
processes are calcium and sodium.
• may also be found directly in the
aggregates as impurities
• They react with calcium hydroxide to
form gypsum
• This process increases the volume of
the concrete by lamination process.

14. LAMINATION OF CONCRETE

15. DETERIORATION BY
CHLORIDES